Process for the preparation of fluorocarbon compounds



United States harem O PROCESS FOR THE PREPARATION OF FLUORO- CARBON COMPOUNDS Donald Fred Knaack, Wilmington, Del., assignor to E. I.

du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Filed Aug. 31, 1959, Ser. No. 836,862

7 Claims. (Cl. 260--653.1)

The present invention relates to the formation of fluorocarbon solvents, and, more particularly, to the formation of internally unsaturated dimers and trimers of hexafluoropropylene.

The internally unsaturated dimers and trimers of hexafiuoropropylene have the general formulas C F and C F and the following structures:

2,983,764 Patented May 9, 1961 EXAMPLES I TO X Into a 180 ml. stainless steel reaction vessel wa' charged at a temperature of 50 C. the monomer, cata lyst and the solvent, when employed, indicated in the table. The reaction mixture was heated to the temperature indicated and agitated at that temperature for the time shown in the table. The resulting insoluble liquid fluorocarbon products were separated from the remaining reaction mixture. Hexafluoropropylene di- OFa 0E3 mers having boiling points at 46 and 505 C. were I l isolated and were identified as perfluoro-4-methyl- CF3 CF CFC| CF3 pentene-Z and perfluoro-Z-methylpentene-Z. Hexafluoro- Fa CF: a a propylene trimers having boiling points at 110 and 114 and CF C. were also isolated and identified as perflu0ro-2,3,5-trimethylhexene-3 and perfluoro-2,3,S-trimethylhexene-Z. Eh- 3 F-C F-C Fa The dimers and trimers were separated by gas chromatogor, F: p y- Table Monomer Catalyst Solvent Dimer- Reaetion Reaction Trtmer Example Temper- Time Product Type wt. Type wt. Type Quantity ature, O. in Hrs in g in g. 111 g. in ml.

I Hexaflu0ropropylene tetlz rxkils (dlmethylamino) 0.86 60 2 19.4

e ene. n do 30 AZ 0.86 Benzene 25 50 '2 17.5 TT do. 30 do 0.86 d 25 200 2 22 IV d3 30 do 0.86 Dimethylformamida. 25 60 2 11 Hexa uoro ropylene 15 V {Tetrafluoro gthylenmnn 10 25 100 2 30 Tetrarnethylguanldine- 0.88 100 2 4.1 30 do. 0.88 Benzene 25 100 2 2.9 30 do 0.88 DimethylsuKox1de.. 25 100 2 21.0 IX p yle 30 do 1.76 100 2 9.8

Tetrafluoroethylene 20 X {Hexafluoropropylene- 30 .-do 1.76 Dimethylformamida. 25 100 2 12.7

"""""" Tetrafluoroethylene 20 I claim:

These compounds are extremely useful as fluorocarbon solvents, since they, although unsaturated, possess a high degree of chemical inertness.

It is one of the objects of the present invention to prepare fluorocarbon solvents. It is another object to prepare internally unsaturated dimers and trimers of hexafluoropropylene. Other objects will become apparent hereinafter.

In accordance with the present invention, it was discovered that internally unsaturated dimers and trimers of hexafiuoropropylene are produced when hexafiuoropropylene is contacted with catalytic amounts of a compound selected from the class consisting of tetramethylguanidine and tetrakis(dimethylamino)ethylene at a temperature in the range of 0 to 250 C. The catalysts employed in the process of the present invention are extremely versatile and active in that they can be employed in the absence of a liquid reaction medium. If desired, the process may, however, be carried out in the presence of a solvent such as dimethyl formamide, dimethyl sulfoxide and benzene. The catalysts employed, furthermore, allow the formation of the hexafluoropropylene 1. Process for the preparation of fluorocarbon solvents which comprises contacting hexafluoropropylene at a temperature of 0 to 250 C. with catalytic amounts of a compound selected from the class consisting of tetrakis (dimethylamino) ethylene and tetramethylguanidine, and recovering a mixture of internally unsaturated, linear dimers and trimers of hexafluoropropylene.

2. The process as set forth in claim 1 at a temperature of 50 to 200 C.

3. The process as set forth in claim 1 in the presence of an inert solvent.

4. The process as set forth in claim 3 wherein the solvent is benzene.

5. The process as set forth in claim 3 wherein the solvent is dimethyl formamide.

6. The process as set forth in claim 3 wherein the solvent is dimethyl sulfoxide.

7. The process as set forth in claim 1 in the presence of tetrafiuoroethylene.

References Cited in the file of this patent UNITED STATES PATENTS 2.691.036 Miller Oct. 5, 1954 

1. PROCESS FOR THE PREPARATION OF FLUOROCARBON SOLVENTS WHICH COMPRISES CONTACTING HEXAFLUOROPROPYLENE AT A TEMPERATURE OF 0 TO 250*C. WITH CATALTIC AMOUNTS OF A COMPOUND SELECTED FROM THE CLASS CONSISTING OF TETRAKIS (DIMETHYLAMINO) ETHYLENE AND TETRAMETHYLGUANIDINE, AND RECOVERING A MIXTURE OF INTERNALLY UNSATURATED, LINEAR DIMERS AND TRIMERS OF HEXAFLUOROPROPYLENE. 